fossula (fos'su-lah)

A little fo a. f. fenestrae oval is. A depre ion in the inner wall of the tympanum above the promontory, in which is situated the oval window for the reception of the foot plate of the stapes, f. fenestrae rotundae. A funnel-shaped depre ion on the inner wall of the tympanum, having the fenestra rotunda at its bottom, f. inferior. A depre ion at the bottom of the internal auditory meatus below the crista falciform is. It presents in its anterior part the lamina cribrosa anterior inferior, and posteriorly the foramen singulare. f. petrosa. A slight depre ion upon the temporal bone in which is situated the inferior aperture of the tympanic canal. f. sulci form is. A slight furrow on the posterior border of the hem i-elliptical fo a which leads from the inner opening of the aqueduct us vestibuli directly toward the crista vestibuli. f. superior. A depre ion in the petrous portion of the temporal bone in which is situated the internal aperture of the aqueduct of Fallopius. [Lat., dim. of fo a, a ditch.]